Hydraulic brake



oci. 29, 1940.

'T. P. CHASE HYDRAULIC BRAKE Filed May 6, 1939 l2 Sheets-Sheet 1 mmmmgs -15A ber oi' the system, the section being indicated wheels respectively o!v a vehicle. The brake Peieciedocf. 29, 1940 uNiTED STATE-s PATENTS# OFFICE mastino BRAKE Theron P. Chase, Detroit, Mich., assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware 'Apciicciiocmcy s, i939, serial No. 272,185

s claims. (ci. 18s- 152) This invention relates to brakes and more pardouble v-piston 43 having an intermediate part ticularly to hydraulicbrake for vehicles. 44 between enlarged heads 45 and 41 fitting the An object of the inventio is to provide a hycylinders35 and 39. Within cylinders 3.1 and 4I draulic system for applying la plurality ofcbrakes is a double piston 49 having an intermediate part 6 from a single -pressuresource and having means 5I and enlarged heads 53 and 55 which t their 5 whereby the pressure upona part of said brakes respective cylinders. 'I'he pistons have packings. may be rendered unlike that upon another part. 51, 59 and 6|. as indicated. Threaded into. the Other-objects will/be understood from the decasing adjacent one end of each cylinder is a scription which follows. plug 63. A spring -55v is positioned between On the drawings: these plugs and the adjacent piston heads. m Figure 1- is a diagrammatic plan of rny1brake `Plugs 61, 61 aresimilarly threaded into casing system applied to the frontv and rear wheel brakes at the other end of these cylinders and springs of a vehicle. 69 are placed between the plugs and the piston .Figure 21s c vertical section through one mmheads 4i and 55- .An intermediate passage beby tween and parallel with the cylinders is shown at 1| in Figure 4'. `At one end, this passage joins a vertical inlet passage 13 communicating with a transverse passage 'I5 within w h` rotates a hollow valve 11. Cylinders'35V and 31 to the left o1' piston 'heads 45 and 53`communicate with -paszo line 2-2 of Figure 4,

Figure 3 is a section `on line 3-3 of Figure-4. Figure 4 is a longitudinal section on line 4-4 of Figure 2. 20 Figures 5iand 6 are sections on line 5-5 and i c n la Y 6 9 respectively oi' Figure 4.' I

Referring-,0 the drawings, numerals] valve 11 is formed withY a central-longitudinal are used to designate theiiront wheels and rear passage 83 from which extend ircumferentially displaced radial passages 8.5,.81and 89 that passage 83 maybe brought into communication with passages 13 and 19 by rotating the valve. `The valve stem 9| 4vextends through a threaded plug 9 3 and carries a manually operable lever 95.

Into `the other en of passage 15 is threaded a `25 drumls for'the wheels Il and i3 are marked-Hf and 3'. 'Ihe master cylinder for applying-thfbrakes is representedv by .numeral |54 No novelty is herein claimed for this master cylinder, nor for the wheel cylinders andshoe assemblies within h the v A pedal I1 is shown operably oonto the conduit 21. At the end of cylinders 39 and nected to rod la for moving the piston, not 4l. adjacent plugs 61 and 91T-is aconnectins shown, of-the master cylinder'. The master lJSSBge HIL/seen in Flgureand communicating' cylinderis connected tothegcylinders'of therear/ with both cylinders.. This passage4 llll .comwheel brelies'by'c pipe line including c. conduit municates with the'. end f passage l-1I and, by

sage 15 by means of passages andI. vThe c hollow plug 91 whih is adapted. to be connected' so" 2| and branch c'onduitsfil'.r Branching from the conduit 2| at 251s -a conduit 21 to conveyhydraulic medium from the master cylinder for applylng-front wheel brakes. Branch conduits 29 '40 and 29' at theiront wheel .brakes unitewith a.

conduit 3| which is operablycoonnected to conduit 21 by means 0 1 al casing 33 containing mechanisnrwhichmaybe manipulated to control the pressurein the `iront wheel brakes and therefore the ratio between the pressure on' the rear cylinders are. located sideby side as shown' in Figure 4.' Cylinder at its-rear end merges passageslll and H3'. It also isopen to the vcylinders 39 and 4| when.-tl `1e pistons are in their i retracted positions. This communication is affordedfbyfpssages |.|5 and ||1.

'.{vhel drawings show the parts in theposition the occupy when the brakes are released'. The reservoir |01 is in. communication with cylinders 35 a'nd 31 between the piston Aheads @and also with c cylinder ai having cA which, is .r less-uien niet. of;v er n. cylinder ai merges with' a I having a diameter' which is larg diameter o! cylinderA .-with` cylinders '39 and 4I-.tor the reason that springs 99 have pushed back both pistons and thereby opened passage 'I I5, H1. The drawings er than the show the valve ,11-'rotated to a position such that isis :1. cylinders. and al there moves' e Aits iongitudinare a: communicates by 'wey I The latter is open to conduit 3|.` When the pedal is depressed thebrakes at the rear wheels are applied in the usual way as are also the front brakes because of the continuous conduitthrough casing 33 as just explained. It it be desired to apply a pressure on the front brakes which shall be le'ss than that of the rear brakes, the valve 11 isv rotated to bring its radial passage 35 into registration with passage Il. When now` the brakes are applied the iiuid mdium is cut oi' from passage 13 nor is it operable upon the piston of cylinder 35. Itl does, however, move piston l! and owingftthe fact that cylinder Il is of' pressure developed for applying the -front brakes.

It may be noted that whenthe central passage 1| is cut oi! and one or the other of the pistons I3 or 49 is being used, the fluid column for applying the front brakes is-indeperident of the `iluid column associated lwith the master cylinder. It`

is for this reason that the reservoir |01 is provided in the casing 33. By means of the removable plug 109 the cylinders 33 and 4 1 mayV be supplied with uid.

I claim: 1. A hydraulic brake system having a rst set of brakes, a second set of brakes, a pressure portions whereby the pressure in said source, a rst conduit between said lsource and said rst set, a second conduit to transmit uid from said source and operable upon said second set, said second conduit having first and/secondl portions, an adjustable means connecting said cond portion may be equal or unequal'to the pressure `amarres oil-passages 81 and 13 l,with the casing passage 1I.'

in said first portion, said adjustable means in'- cluding an auxiliary brake applying means and a valve movable to a position whereby said por.

tions may be directly connected or to a position to divert the ow to said'auxiliary'means to change the ratio of pressures in said portions and 'reservoir means associated with said auxiliary brake applying means. f

2. Aphydraulictbrake system having a rst set of brakes, a second set of brakes, a. pressure source, a rst conduit between said source and said ilrst set, a second conduit to transmit fluid from said source and operable upon said second set, said second conduit having Viirst and second portions, an adjustable means connecting said portions whereby the pressure in said second portion may. be equal or unequal to the pressure in said flrst portion, said-adjustable means including a plurality of pressure changing means and a'valve whereby Athe portions maybe direct- `ly connected or may-be moved to connect the iirst portiomwith either of said pressure changingmeans. J

N3. A hydraulic brake system having a first set of brakes, a second set of brakes, a pressure source, a rst cond said first set, a second duit to transmit iluid from said source and operable uponsaid second set, said second conduit having first and second portionsl an adjustable means connecting said portions whereby the pressure in said second portion may be equal or unequal to the pressure in said iirstportion, said adjustable m'eans including a plurality of pressure changing means and a valve` whereby the portions -may be directly connected or may be moved to connect the ilrstportion with eitherl of said pressure changing means, each of said pressure changing means including a pistonhaving iirst and second unequally dimensioned heads, said valve opera from the rst portion to one o said heads, the other of said heads being operable to transmit fluid to said second portion.

THERoNP. CHASE.

between said source andl 

